A few thoughts/ observations/ speculations ....
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First, you can't change the spring rate with the touch of a button, you can only raise or lower the car. <explanation follows>
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The amount of "wallowing in hte corners" will depend on the type of bag used.
There is the style of air sack that is really nothing but a bag of air, the greater the load the more it compresses and the spring rate is somewhat lineal.
Then there is the type of sack that has a "conical" end (more parabolic). The more weight/ force applied collapses the sack moving the cone into the bag reducing the volume and effectively increasing the spring rate.
I bet one could go through lots of money buying bags of different diameter and length with different cone configurations before finding one that suits them
just right.
A bag that was 'perfect' on my V6 car probably wouldn't cut it in my Windsor car.
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The range of motion things a good point. But if both ends of the sack are on pivots that will allow them to pivot and self align thus staying somewhat paralell this isn't / wouldn't be a concern. Believe me, bags under pressure want to align themselves.
There is a certain amount of swing bags with fixed ends will tolerate. I think the front of a II would excede this tolerance.
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I wonder how much of the wallowing in corners are due to the air bags supply lines being 'T"ed together instead of being valved seperately. ? Even if the 'perfect' bag is used it can still wallow like a SOB. Go into a corner and the outside bag collapses thus increasing pressure which is transmitted through the line to the bag on the corners inside which tends to extend it. YeeHaw! Just imagine an exit ramp ...... will it ever stop rolling to the outside???
Each bag needs it's own valving.
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You can't use the shock mount points for an airbag without reinforcing the hell out of the mounting points. Shock mounts are designed to absorb forces from dampening
suspension movement, their not designed to support a load. This is the problem with air shocks. In days of old it wasn't unheard of to have air shock tops protruding into the trunk.
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An air bag and a shock absorber can't share the same space unless the bag has a hollow center. I have never heard of a bag with a hollow center. There would need to be an alternate layout for the shock.
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Never thought about this before ....